Method of trimming gates of die castings



' May 8, 1945.

| H MORIN METHOD OF TRIMMING GATES OF DIE CASTINGS Filed Jan. 15, 1943 INVENTO 100/5 A4 Max? BY 5 Y U ATTQRN YS Patented May 8, i945 Louis H. Morin, Bronx, N. Y., assignor of onehfllf to Davis Marinsky, BI'ODX, N- Y.

Application January 15, I943, Serial No. 472,492

1 Claim.

This invention relates to the formation of die castings including gate portions where the casting is formed on a core, the latter serving to eject the castings from the dies in the separation of said dies. a

It is an object of this invention to provide an improved method of handling and finishing die castings.

In accordance with the invention, a casting, including a gate or sprue, is formed on a core. While the casting is still supported on the core, the gate or sprue is trimmed from the casting and then the latter is stripped from the core.

The invention will be defined in the claims and illustrated by the following description when taken together with the accompanying drawing, in which certain embodiments of apparatus adapted for practicing the method of the invention are disclosed, and in which the separate parts are designated by suitable reference charshowing parts lower end of the core 20. The passage 2|, where it joins the cavity I4 is contracted, as seen at 23, to form on the resulting gate 24a weakened end 25 which facilitates removal of the gate 24 and dispenses with the use of a sharp trimming tool. It will here be understood, however, that in some instances sharp trimming tools may be employed to actually shear the gate adjacentor at the periphery of the casting.

The trimming tool, l2 in the constructio shown, comprises a bar movable transversely with respect to movement of the core 20, and has at its inner end an aperture or pocket 26 to receive the gate 24 when the core 20 is lowered to the trimming position, as shown in full lines in Fig. 1. After the core has been moved into this position, the stri per tool l3 is moved in the direction of the core 20 so that the forked end of 21 thereof envelopes the core, as seen in Fig. 1. I

The trimming tool 12 is now moved in the direction of the arrow 28 as indicated by the dotted lines in Fig. 1, which results in removing or trimming the gate 24 from the casting l5. Immediately upon completion of this operation, the core '20 is then moved upwardly in the direction of the arrow 29 of Fig. 2, which results in stripping the casting litherefrom by the strip- Fig. 4 is a view similar to Fig. 3, showing parts in a different position.

In the accompanying drawing, different forms of apparatus are diagrammatically shown adapted for the practice of the method of the invention. v

Figs. 1 and 2 of the drawing show the various parts of the apparatus diagrammatically and also in what might be termed exaggerated relationship, particularly in that the two die parts l0 and II are shown in wide spaced relationship in order to clearly illustrate the gate trimming tool or member l2 and the stripper l3.

On abutting surfaces of the dies l0 and II are cavities or impressions I4 which collectively form what may'be termed a button shank l5, comprising as noted in Fig. 2, a disc like body It with a depending ring or eye portion H. The disc It has an aperture I8 in the upper surface thereof, formed by the reduced end IQ of a core pin 20.

Also formed on the abutting surfaces of the dies I0 and H are admission passages 2| through which castingmaterial from an injection nozzle tracted position, the dies l0 and II again moved into closed position upon the core 20, the nozzle brought into engagement with the dies, and the next successive casting is formed.

After the casting is formed, the dies Ill and II are separated as indicated in Fig. 1, leaving the casting l5 supported on the core 20 as indicated in the dotted position of these parts in Fig. 1, the core 20 being used to eject the castings from the impressions I4. Thereafter, the above operation is again repeated to trim and eject the next successive casting.

Castings of this'type and kind can be produced at high rates of speed, and will result in production of finished products, except where plating and other operations might be desirable.

It .will be understood that the particular article or casting shown in the accompanying drawing is simply illustrative of one of many types and kinds of castings which can be produced in this manner. Where mass productionis desired and excessive handling'dispensed with for the purpose of minimizing, to the greatest degree, the cost of production, suitable means substituting for the trimming tool l2 and stripper IS, a combined trimming tool 30 and stripper 3|, arranged'upon the core 20 above the dies III-l I, instead 01 beneath the dies, as shown in Figs. 1 and 2. a

With this construction and method of operation, the core 20 moves upwardly when the dies lO-Il are separated; instead of moving downi be held stationaryand the tools 30, 3| 'moved downwardly in performing their combined t'rimsired results. In other instances, the trimming operationsuch as shown in Figs. 1 and 2 will be desirable and some times necessary.

It will also be apparent from a consideration of Figs. 3 and 4 of the drawing that where the dies are separated sufficiently, the core 20 may ming and stripping operations.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:

'The method of trimming gate portions from I die castings, which comprises first forming a die wardly as in Figs. 1- and 2. The trimmingand stripping tools 30, 3| are held stationary, and as the tool 30 projects below the lower surface ofth'e stripper 3|. this tool will first engage the gate 24 of the casting IE to remove or trim it from the casting, after whichthe continued upward movement of. the core will result in stripping the casting l5 from the core, as is illustrated in Fig. 4 of the drawing.

Inscme types and kinds of casting, the method or procedure as illustrated in Figs. 3 and 4, would .be desirable over the method illustrated in Figs.

1 and 2; particularly in that less moving parts are employed and further where a trimming operation of this kind is suflicient to produce the de- 35 casting between relatively movable dies and on a core arranged on the parting line of the dies, by injecting casting material through a gate passage on the parting line 01' the dies into the mold cavity of said die and around said core, then separating the dies, leaving the casting including a gate portion supported on said core, then moving the core with the casting thereon to a trimming position, holding said casting stationary so that'it may not rotate about the longitudinal axis of said core, then moving a trimming tool transversely with respect to the direction of movement of the core to trim the gate from the casting while supported on the core, and then moving the core and casting in the opposite direction and relatively to a stripper tool arranged between and in spaced relation to the trimming tool and dies in stripping the trimmed casting from said core.

LOUIS H. MORIN. 

